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Characterising the properties of the atmospheric emission at Teide Observatory in the 10-20 GHz range with QUIJOTE data
No full textInternational audienceQUIJOTE is a CMB experiment composed of two telescopes, QT1 and QT2, located at the Teide Observatory in Tenerife, Spain. The MFI instrument (2012-2018), installed on QT1, observed the sky at four frequency bands (11, 13, 17, and 19 GHz) with one degree angular resolution. Its successor, MFI2, began operations in 2024 and operates in the same bands. This paper has two main goals: first, to characterise the atmospheric conditions at Teide Observatory to improve existing models at these frequencies, and second, to empirically characterise atmospheric turbulence using QUIJOTE MFI and MFI2 observations. This work has implications for both atmospheric physics and CMB studies and can support future reanalyses of MFI data or the preparation of upcoming instruments such as the Tenerife Microwave Spectrometer. We used data from GPS antennas, the STELLA observatory, and radio soundings to derive median profiles and distributions of key atmospheric parameters for 2012-2018. MFI data were analysed to compute atmospheric structure functions at 17 and 19 GHz and to study the correlation properties of the atmospheric signal through cross-correlation between horns at the same frequency. MFI2 observations were used to estimate the atmospheric power spectrum and compare it with the structure function derived from MFI data. The water vapour density profile follows an exponential decay with a characteristic half-height of about 1000 m. Median PWV in 2012-2018 is 3.3 mm. For high PWV conditions, the structure function agrees with the Kolmogorov turbulence model. The slope of the power spectrum also matches the model prediction, within the frequency range limited by the outer scale and instrument noise. Finally, from the correlation function, we find that atmospheric conditions remain stable for about 1-2 hours
Parametric strong lensing model of the galaxy cluster Abell 2390 from Euclid and MUSE observations
No full textInternational audienceWe present a new high precision parametric strong lensing total mass reconstruction of the Euclid Early Release Observations (ERO) galaxy cluster Abell 2390, at redshift z = 0.231. We include in this analysis 35 multiple images from 13 background sources, of which 25 are spectroscopically confirmed thanks to observations from the MUSE, spanning a redshift range from z = 0.535 to z = 4.877. After fully reanalysing the MUSE spectroscopy, we combine it with archival spectroscopic catalogues allowing us to select 65 secure cluster members. This sample is further complemented with 114 photometric member galaxies, identified within the Euclid VIS and NISP imaging down to magnitude H = 23. We also measure the stellar velocity dispersions for 22 cluster members, in order to calibrate the Faber-Jackson relation and hence the scaling relations for the subhalo mass components. We test and compare 11 total mass parametrisations of the galaxy cluster with increasing complexity. To do so, we employ the new parametric strong lensing modelling code Gravity.jl. Our best fit total mass parametrisation is characterised by a single large scale halo, 179 subhalo components, and an external shear term. The reference model yields a mean scatter between the model predicted and observed positions of the multiple images of 0.32 arcseconds. We are able to quantify the systematics arising from our modelling choices by taking advantage of all the different explored total mass parametrisations. When our results are compared with those from other lensing studies, we notice an overall agreement in the reconstructed cluster total mass profile in the outermost strong lensing regime: the discrepancy in the innermost region of the cluster (few kiloparsec from the brightest cluster galaxy, where few or no strong lensing features are observed) could possibly be ascribed to the different data and modelling choices
MEGATRON: the impact of non-equilibrium effects and local radiation fields on the circumgalactic medium at cosmic noon
No full textInternational audienceWe present three cosmological radiation-hydrodynamic zoom simulations of the progenitor of a Milky Way-mass galaxy from the MEGATRON suite. The simulations combine on-the-fly radiative transfer with a detailed non-equilibrium thermochemical network (81 ions and molecules), resolving the cold and warm gas in the circumgalactic medium (CGM) on spatial scales down to 20 pc and on average 200 pc at cosmic noon. Comparing our full non-equilibrium calculation with local radiation to traditional post-processed photoionization equilibrium (PIE) models assuming a uniform UV background (UVB), we find that non-equilibrium physics and local radiation fields fundamentally impact the thermochemistry of the CGM. Recombination lags and local radiation anisotropy shift ions away from their PIE+UVB values and modify covering fractions (for example, HI damped Ly absorbers differ by up to 40%). In addition, a resolution study with cooling-length refinement allows us to double the resolution in the cold and warm CGM gas, reaching 120 pc on average. When refining on cooling length, the mass of the lightest cold clumps decreases tenfold to , their boundary layers develop sharper ion stratification, and the warm gas is better resolved, boosting the abundance of warm gas tracers such as CIV and OIII. Together, these results demonstrate that non-equilibrium thermochemistry coupled to radiative transfer, combined with physically motivated resolution criteria, is essential to predict circumgalactic absorption and emission signatures and to guide the design of targeted observations with existing and upcoming facilities
Measurements of quasar proximity zones with the Lyman- forest of DESI Y1 quasars
No full textInternational audienceThe intergalactic medium (IGM) around quasars is shaped by their dense environments and by their excess ionizing radiation, forming a "quasar proximity zone" whose size and anisotropy depend on the quasar's halo mass, luminosity, age, and radiation geometry. Using over 10,000 quasar pairs from the Dark Energy Spectroscopic Instrument (DESI) Year 1 data, with projected comoving separations , we investigate how the proximity zone of foreground quasars at affects Lyman-alpha absorption in their background quasars. The large DESI sample enables unprecedented precision in measuring this "transverse proximity" effect, allowing a detailed investigation of the signal's dependence on the projected separation of quasar pairs and the luminosity of the foreground quasar. We find that enhanced gas clustering near quasars dominates over their ionizing effect, leading to stronger absorption on neighboring sightlines. Under the assumption that quasar ionizing luminosity is isotropic and steady, we infer the IGM overdensity profile in the vicinity of quasars, finding overdensities as high as at comoving distance from the most luminous systems. Surprisingly, however, we find no significant dependence of the proximity profile on the luminosity of the foreground quasar. This lack of luminosity dependence could reflect a cancellation between higher ionizing flux and higher gas overdensity, or it could indicate that quasar emission is highly time variable or anisotropic, so that the observed luminosity does not trace the ionizing flux on nearby sightlines
Clustering redshift distribution calibration of weak lensing surveys using the DESI-DR1 spectroscopic dataset
No full textInternational audienceWe estimate the source redshift distribution of current weak lensing surveys by applying the clustering-based redshift calibration technique, using the galaxy redshift sample provided by the Dark Energy Spectroscopic Instrument Data Release 1 (DESI-DR1). We cross-correlate the Bright Galaxy Survey (BGS), Luminous Red Galaxies (LRGs) and Emission Line Galaxies (ELGs) from DESI, within the redshift range , with overlapping tomographic source samples from the Dark Energy Survey (DES), Kilo-Degree Survey (KiDS), and Hyper Suprime-Cam (HSC) survey. Using realistic mock catalogues, we test the stability of the clustering-redshift signal to fitting scale, reference-sample choice, and the evolution of source galaxy bias, and we explicitly model and marginalise over magnification contributions, which become non-negligible at due to the depth of the DESI ELG sample. We then compare the resulting bias-weighted redshift distributions to those calibrated using self-organising map (SOM) techniques, finding agreement within uncertainties for all surveys and tomographic bins. Our results demonstrate that clustering redshifts enabled by DESI's unprecedented spectroscopic sample provides a robust, complementary, and independent constraint capable of reducing one of the dominant systematic uncertainties in weak lensing cosmology
Une association inédite entre Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Achromobacter sp. et un isolat environnemental d’amibe libre
No full textInternational audienceObjectif : La colonisation du tractus respiratoire des patients atteints de mucoviscidose (CF) est un processus évolutif et polymicrobien, influencé par l’âge, l’état clinique, l’exposition environnementale et les traitements antibiotiques. Plusieurs bactéries opportunistes CF – comme Mycobacterium avium, Pseudomonas aeruginosa, Stenotrophomonas maltophilia ou Burkholderia cepacia – ont déjà été décrites comme capables de survivre ou de se multiplier dans des amibes libres (FLA). Très présentes dans les réseaux d’eau, ces protozoaires se nourrissent de bactéries par phagocytose mais peuvent également héberger des bactéries capables de résister à la digestion et d’y persister. Bien que les caractéristiques cliniques des pathogènes CF soient bien connues, leurs réservoirs environnementaux et voies d’acquisition respiratoire restent peu étudiés. Si certaines de ces espèces ont déjà été observées individuellement dans des FLA, leur co-hébergement dans une même FLA n’a jamais été documentée.Méthodes : L’ADN d’un isolat environnemental de FLA, incluant celui de ses bactéries associées, a été séquencé par métagénomique. Après assemblage, le génome des microorganismes a été reconstitué par une approche de binning pour caractériser leur taxonomie.Résultats : L’assemblage métagénomique a permis d’obtenir un génome fragmenté de l’amibe hôte appartenant au phylum Heterolobosea, composée de 53 783 contigs (23 949 ≥ 1kb), avec un contenu GC de 41,8 % et un N50 de 3198pb. En parallèle du génome amibien, trois génomes bactériens distincts ont été reconstruits à plus de 92 %. Ils correspondent, de manière surprenante, à trois pathogènes opportunistes majeurs dans la mucoviscidose : P. aeruginosa ST 549, S. maltophilia et Achromobacter sp. Cette co-occurrence tripartite représente, à notre connaissance, la première preuve génomique d’une FLA hébergeant simultanément ces trois pathogènes majeurs de la mucoviscidose.Conclusion : Nos résultats renforcent l’idée que les FLA peuvent servir de réservoirs environnementaux multi-pathogènes CF, favorisant potentiellement leur persistance et leur transmission. Ces observations soulignent la nécessité d'intégrer la surveillance environnementale et le séquençage génomique dans l’étude des dynamiques d’infection et des voies de transmission des pathogènes liés à la mucoviscidose
Selection of Chemical Adsorbents and Operating Conditions for the Injection Traps of the Gas Chromatograph on Board the Dragonfly Mass Spectrometer
No full textInternational audienceThe Dragonfly mission is set to explore Titan’s surface in the mid-2030s. This relocatable lander is equipped with the Dragonfly Mass Spectrometer (DraMS) instrument. One of DraMS functioning mode is gas chromatography−mass spectrometry, to identify organic compounds in solid samples. DraMS-GC includes two independent chemical injection traps to focus the molecules released from the sample. Initially, Tenax TA was planned to be the adsorbent in the injection traps because of its heritage in previous space probes. However, Tenax TA has shown some decomposition products that challenge the identification of the molecules indigenous to the sample. In this work, the performance of another adsorbent powder, Carbotrap C, was compared to Tenax TA. Performance was evaluated in DraMS-like desorption conditions by comparing the recovery yield after adsorption and desorption of a set of 53 organic compounds of interest to Titan. Recovery with Carbotrap C was either similar or better than with Tenax TA for 79% of compounds. This recovery yield was further improved by increasing the desorption temperature. DraMS low desorption flow rate appears to be the most limiting parameter for recovery. Desorption from both Tenax TA and Carbotrap C led to partial but comparable racemization for three of the four amino acids that were enantiomerically resolved. Together, these results led to the integration of Carbotrap C in one of the DraMS injection traps
Projet SARHAE - Le site archéologique des Rothenstauden à Voellerdingen (67) étude d’un habitat antique et de son environnement - Rapport d’opération 2025
No full textLe site archéologique des Rothenstauden est localisé sur la commune de Vœllerdingen, dans le département du Bas-Rhin. Il fait depuis 2021 l’objet du programme pluridisciplinaire « SARHAE : Le site des Rothenstauden – Vœllerdingen (67) - Étude pluridisciplinaire d’un habitat antique et de son environnement ». L’année 2025 a notamment été marquée par la poursuite de la fouille extensive dans le secteur 100 (avec la réalisation d’un conséquent protocole de prélèvement). En raison des conditions météorologiques, cette opération n’a pas pu être achevée comme prévue. Elle a tout de même permis de mettre au jour les premiers niveaux d’occupations au sein de ce secteur de la pars rustica de la villa et de constater qu’il a connu de nombreuses phases d’évolutions. Suite à une première période d’aménagement (laténienne ?), la zone est dévolue à des activités liées au feu au début de l’Antiquité. Entre la fin du Ier s. ap. J.-C. et le IIe s., le bâtiment maçonné est construit. Il va connaître plusieurs périodes d’aménagements et sans doute plusieurs fonctions jusqu’au IIIe s., où il sera abandonné.En parallèle de la fouille, d’autres travaux ont été menés au cours de l’année 2025. De nouvelles études géomorphologiques et pédo-sédimentaires ont été réalisées et l’analyse des données LiDAR et géophysiques a été approfondie. Ce volet permet désormais d’avoir une bonne image de l’étendue du site et de la composition de son environnement qui est structuré par un vaste parcellaire. À partir de 2026, il s’agira de réaliser de nouveaux sondages exploratoires pour valider certaines observations et hypothèses.Si des zones d’ombres persistent encore et si les problématiques scientifiques sont encore loin d’avoir trouvé toutes leurs réponses, le projet SARHAE a déjà permis d’obtenir, depuis son lancement en 2021, de nombreuses données sur le site archéologique des Rothenstauden et sur son environnement. En outre, la démarche employée a permis de tracer plusieurs pistes méthodologiques sur l’étude des vestiges archéologiques sous forêt. Les travaux prévus au cours des prochaines années viendront progressivement compléter les données sur les relations entre une villa et son environnement, sur son fonctionnement et plus globalement sur l’histoire des espaces qui sont actuellement sous forêt
Sediment routing and palaeogeographic evolution of the Western Alpine Foreland Basin during the early collisional stage
No full textInternational audienceIn the Western Alpine Foreland Basin (WAFB), Late Eocene and Miocene periods were characterized by longitudinal sediment routing systems: The first one was situated within the turbidite basin during the underfilled phase and exhibited a northward orientation toward the Swiss Basin, whereas the second was located in the Rhône Valley during the overfilled phase and was directed southward toward the Mediterranean Sea. The transition between these two periods occurred during the Oligocene, which corresponds to both the underfilled/ overfilled transition and the early overfilled period. In this study, we provide new fieldwork observations, seismic and well data interpretations, biostratigraphic analyses and a literature synthesis to reconstruct the palaeogeographic and source-to-sink evolution of the WAFB from Priabonian to Aquitanian. The aim is to discuss this reorganisation of sediment routing in relation to the evolution of the Alpine orogenic wedge, as well as the structural inheritance and the suite of geodynamic events that affected southeastern France during the mid-Cenozoic. We divided the WAFB sedimentary formations into four depositional sequences (S1 to S4). During the deposition of the first two sequences (Priabonian to early late Rupelian; ~37.4-28.8 Ma), the WAFB routing system was influenced by the end of the Pyrenean-Provençal orogeny, the European Cenozoic Rifting System (controlling the Rhône Valley s.l.) and the Alpine orogenic wedge (controlling the Alpine foredeep). The very first connection between the Alpine domain and the Rhône Valley is established at ~30 Ma, during the late Rupelian (S2 highstand), controlled by E-W inherited Pyrenean-Provençal structures implying a 'broken foreland'. In the meanwhile, from the Dévoluy Basin and northward, the orogenic wedge controlled a classical, although thin, foreland basin characterized by a northward sediment routing connected to the Northern Alpine Foreland Basin. Most of the S3 sequence (Latest Rupelian to middle Chattian; ~28.8-23.25 Ma) corresponds to a decrease of clastic Alpine inputs throughout SE France caused by a reorganisation of the drainage network related with the exhumation of the southern External Crystalline Massifs. S3 highstand and S4 sequence (late Chattian to Aquitanian; from ~23.25 Ma) correspond to the establishment of a longitudinal sediment routing system in the Rhône Valley, with material flowing southwards toward the Gulf of Lion, and supplied by the Palaeo-Isère to the north and potentially by the Palaeo-Durance to the south. This final stage in the reorganisation of the drainage network is clearly associated with the post-rift phase of the Gulf of Lion, which facilitated the opening of a new sink and the ultimate southward migration of the sedimentary area
Soil organic matter decomposition in semi-arid mangrove stands (New Caledonia)
No full textInternational audienceOrganic matter (OM) dynamics in mangrove forests have been studied extensively in terms of the capacity of their soils to store organic carbon. While δ13C, δ15N, and C/N values for mangrove soils and sources are well reported, other indicators of OM maturity and composition are lacking. In this study, soil OM decomposition processes were investigated for a semi-arid bay head mangrove forest in New Caledonia. Mangrove tissues and 20-cm soil cores were collected in monospecific stands of Avicennia marina and Rhizophora stylosa. The isotopic compositions of the samples were assessed, along with their molecular compositions (lignin-derived phenols and neutral carbohydrates). Rock-Eval analysis was also performed on the samples to investigate OM characteristics. Results showed that stable isotope ratios and Rock-Eval parameters followed similar vertical trends beneath both species indicating the influence of depth on OM state. However, the more anoxic conditions beneath R. stylosa limited OM decomposition as shown by the lower TpS2 values (indicator of OM thermal stability). Neutral carbohydrates and, surprisingly, lignin-derived phenols, were lost at higher rates than bulk organic carbon beneath both mangrove species. Selective degradation of individual compounds was observed, and species-dependent variations associated with the redox conditions and the OM sources were identified. We suggest that lignin was degraded, even in anoxic environments, because of the amount of labile lignocellulosic components in the soil. These findings enhance our understanding of OM dynamics in mangrove ecosystems, shedding light on the mechanisms underlying carbon cycling and their implications for global carbon storage and ecosystem management